D:\ProPlus.WW\OSETUP.DLL digital signature does not validate or is not present

The steps stated in the Microsoft support site are useless. My software too (Office 2010 Professional Plus DVD) has the osetup.dll missing error. My problem is that I am unable to copy the 'troubled' software to the harddisk in order for me to move ahead and do the other steps to replace the errant dll.

I am unable to copy contents from the DVD to the harddisk, because I get the error message "cannot copy.... cyclic redundancy check." There is no support available anywhere I checked, for this situation.

I purchased Office 2010 original DVD 5 months ago. I was able to install the DVD then. Due to problems related to add-ins which started crashing MS Word and MS Excel recently,  Microsoft support asked me to uninstall the software and reinstall. I uninstalled successfully. Now, I am unable to re-install. Now, even MS support is unable to help. They have (over phone) spent over 6 hours of my time in the last 3 days. They are struggling for solutions. The retailer who sold the DVD is asking me to contact Microsoft for further instructions. I am stuck!

I know people who use pirated software without any such problems. I have always used legal software. Is this punishment for purchasing original software?

Cheers, Mahesh

Hey, amen brother!  I get the "digital signature" error and have tried everything on these forums.  So have you found a way to get yours installed and activated?

Try the steps mentioned under Method 3 (Option 2) in the article below and then check if you’re able to install Office.

http://support.microsoft.com/kb/924619

If the issue still persists, then download Office Professional 2007 from the link below and then try to install it using the product key that you have.

http://www.microsoft.com/office/trial/professional.aspx

I finally figure out the fix. Ok first, you have to use Internet Explore to download properly. If you are using IE9 then you have to run it in compatibility mode back to IE8. Once you have done this, then go to the download page and and download office 2010 32bit version. I guess the guy at Microsoft said that the 64bit version was having some issues on 64bit operating systems (you can download either or though and they will both work). After that you should use the Microsoft download manager (you may need to install java and active X). This is what fixed it for me and I hope it fixes it for you too. When I tried the first few times I was using firefox, it is important to follow the internet explore compatibility view steps. Hope this helps!

I've tried all those steps - and everything else.  Any other suggestions to get my Pro Plus 2010 installed and activated?  Help!